Synergistic antimicrobial compositions containing methylene-bis(thiocyanate) and an organic acid

ABSTRACT

Compositions for controlling the growth of microorganisms in or on a product, material or medium comprising synergistically effective amounts of methylene-bis(thiocyanate) and at least one organic acid, its salt or ester are disclosed. Methods to control the growth of microorganisms and prevent spoilage caused by microorganisms with the use of the compositions of the present invention are also disclosed.

This is a division of application Ser. No. 08/187,075, filed Jan. 27,1994, now U.S. Pat. No. 5,441,979.

The present invention relates to certain compositions and processesuseful for controlling the growth of one or more microorganisms and forpreventing spoilage caused by bacteria and fungi in various products,materials or media, particularly industrial products, materials ormedia. These products, materials or media include paints, leather, wood,wood pulp, wood chips, starch, proteinaceous materials, lumber, animalhides, vegetable tanning liquors, cosmetics, toiletry formulations,acrylic latex paint emulsions, adhesives, coatings, metalworking fluids,cooling tower water, textiles, petrochemicals, pharmaceuticalformulations, geological drilling lubricants, paper mill liquors, andagrochemical compositions.

The novel compositions and processes incorporating the composition ofthe present invention show unexpected, synergistic activity againstmicroorganisms, including bacteria and fungi. Specifically, theinvention is directed to the use of compositions and processescontaining methylene-bis(thiocyanate) and at least one organic acid, itssalt or ester.

Many of the products, materials or media referred to above, when wet orsubjected to treatment in water, are susceptible to bacterial and/orfungal deterioration or degradation unless steps are taken to inhibitsuch degradation or deterioration. To control deterioration ordegradation caused by microorganisms, various industrial microbicidesare used, but some of these biocides are of questionable utility becausethey have undesirable odors, are high in cost, show a low degree ofeffectiveness and/or create hazards with respect to storage, use and/orhandling.

For instance, the use of such popular industrial microbicides asorganomercury compounds, organotin compounds and chlorinated phenols hascome under increasing regulatory pressure in recent times because oftheir high toxicity and concern about their adverse effects on theenvironment. Consequently, the industry has continued to seek improvedbiocides that have low toxicity and are capable of exhibiting prolongedbiocidal effect at normal use levels.

Organic acids can be used alone to control microorganisms, and whilesome of these compounds are generally regarded as safe, many of themhave low efficacy against bacteria and fungi unless extremely highconcentrations are used. In excessive concentrations, these organicacids can be expensive and could even be corrosive to certain industrialmaterials. A method that can prevent excessive use of organic acids andhence decrease cost is therefore desirable.

Alternatively, methylene-bis(thiocyanate) can be used alone in lowconcentrations as low toxicity biocides. However, at low concentrations,methylene-bis(thiocyanate) tends to have a narrow antimicrobial spectrumand fails to completely prevent the growth of microorganisms.

Accordingly, the present invention is directed to microbicidalcompositions and processes incorporating these compositions thatsubstantially obviate one or more of the problems, limitations, anddisadvantages of the prior art. In particular, the compositions of thepresent invention are capable of controlling the growth of at least onemicroorganism, especially fungi or bacteria, over prolonged periods oftime, and are safe and economical to use. The present invention also isdirected to methods or processes of controlling the growth of at leastone microorganism.

The present invention provides a composition to control the growth of atleast one microorganism comprising synergistically effective amounts ofmethylene-bis(thiocyanate) and at least one organic acid, its salt orester. The composition provides superior microbicidal activity at lowconcentrations against a wide range of microorganisms.

The present invention also provides a method for controlling the growthof at least one microorganism in or on a material or medium susceptibleto attack by the microorganism which comprises the step of adding to thematerial or medium a composition of the present invention, where thecomponents of the composition are present in synergistically effectiveamounts.

Furthermore, the present invention provides a method of preventingspoilage of a product, material or medium caused by bacteria and/orfungi comprising the step of adding to the product, material or medium,a composition of the present invention where the components of thecomposition are present in synergistically effective amounts.

The synergistically effective amounts vary in accordance with thematerial or medium to be treated and can, for a particular application,be routinely determined without undue experimentation by one skilled inthe art.

The present invention also embodies the separate addition ofmethylene-bis(thiocyanate) and at least one organic acid, its salt orester to the products, materials or media described above. According tothis embodiment, the components are individually added to the system sothat the final amount of methylene-bis(thiocyanate) and at least oneorganic acid, its salt or ester present in the system at the time of useis that synergistically effective amount required to control the growthof at least one microorganism.

The compositions of the present invention are also useful in preservingvarious types of industrial products, media or materials that aresusceptible to attack by microorganisms. Such products, media ormaterials include but are not limited to dyes, pastes, lumber, leather,textiles, pulp, wood chips, tanning liquors, paper mill liquors, polymeremulsions, paints, paper and other coating and sizing agents,metalworking fluids, geological drilling lubricants, petrochemicals,cooling water systems, pharmaceutical formulations, cosmetics andtoiletry formulations.

The compositions can also be useful in agrochemical formulations for thepurpose of protecting seeds or crops against microbial spoilage.

Additional advantages of the invention will be set forth in part in thedescription which follows, and in part will be obvious from thedescription, or may be learned by the practice of the invention. Theadvantages of the invention may be realized and obtained by means of theelements and combinations particularly pointed out in the claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the present invention as claimed.

When two chemical microbicides are combined into one product or addedseparately three results are possible:

1) The chemicals in the product would produce an additive (neutral)effect.

2) The chemicals in the product would produce an antagonistic (negative)effect, or

3) The chemicals in the product would produce a synergistic (positive)effect.

An additive effect has no economic advantage over the individualcomponents. The antagonistic effect would produce a negative impact.Only a synergistic effect, which is less likely than either an additiveor antagonistic effect, would produce a positive effect and thereforepossess economic advantage.

It is well-known in the microbicidal literature that there is notheoretical method to provide the likelihood of knowing, before actuallytesting, whether additive, antagonistic or synergistic effects will beobtained when two biocides are mixed to yield a formulation.

The microbicidal compositions combining methylene-bis(thiocyanate) andat least one organic acid, its salt or ester demonstrate an unexpected,synergistic effect compared to the respective components alone. Thusthese compositions achieve superior, i.e. greater than additivemicrobicidal activity at low concentrations against a wide variety ofmicroorganisms. Examples of microorganisms include fungi and bacteriasuch as, but not limited to, Trichoderma hazianum and Pseudomonasderuginosa. These two organisms are some of the most common organismsassociated with spoilage of products, materials or media. Since thesetwo are also some of the toughest organisms to control, the compositionof the present invention is believed to be effective against mostbacteria and fungi. Preferably, the compositions of the presentinvention have a low toxicity.

The preparation of methylene-bis(thiocyanate) (MTC) is described in U.S.Pat. No. 3,524,871, which disclosure is fully incorporated by reference.MTC is commercially available and also easily synthesized fromcommercially available raw materials. A preferred MTC according to thepresent invention is 2-methylene-bis(thiocyanate).

The organic acids of the present invention are any organic acid thatproduce a synergistic effect when combined with the MTC. Examples oforganic acids include aromatic organic acids, cyclic organic acids,aliphatic organic acids, their salts or esters. Specific examples ofeffective organic acids according to the invention include dehydroaceticacid, octanoic acid, nonanoic acid, formic acid, sorbic acid, aceticacid, oxalic acid, glycolic acid, citric acid, gluconic acid, malicacid, propionic acid, lauric acid, undecylenic acid, benzoic acid orderivatives of benzoic acid such as 2-hydroxybenzoic acid,3-hydroxybenzoic acid or 4-hydroxybenzoic acid, methyl paraben or propylparaben.

The salts of the organic acids, preferably those containing calcium,zinc, potassium, or sodium, may be used, such as sodium benzoate andpotassium sorbate. Preferred esters are parabens such as methyl parabenand propyl paraben.

In accordance with the present invention, mixtures of these organicacids, salts or esters can also be used. When such mixtures are used incombination with MTC, at least one of the organic acids in the mixtureshas a synergistic relationship with MTC. Organic acids, salts and estersuseful in the invention are commercially available or may be synthesizedfrom commercially available raw materials.

The organic acid may be chosen, for example, based on the compatibilityof the acid with the products, materials or media. The compatibility isreadily determined by adding the organic acid to the products, materialsor media to be used.

Compatibility may be determined by criteria such as solubility in afluid system and/or lack of reactivity with the fluid in question. Whenused in a fluid system, for example, it is preferable that the organicacid be freely soluble or dispersible in the particular fluid system,resulting in a uniform solution or dispersion. Examples of fluid systemsare tanning liquor, paper mill liquor, cooling tower water, and paints.

In accordance with the present invention, the composition may be in theform of a solid, dispersion, emulsion or solution, depending on theparticular application Further, the components of the composition may beapplied separately or may be combined first and then applied to theproduct, material or medium. The composition of the present inventionmay be prepared in liquid form by dissolving components (A) and (B) inan organic solvent.

In the following discussion of preferred embodiments, component (A) is2-methylene-bis(thiocyanate) and component (B) is at least one organicacid, its salt or ester.

As described above, components (A) and (B) of the composition are usedin synergistically effective amounts. The weight ratios of (A) to (B)vary depending on the type of microorganisms, as well as the products,materials or media to which the composition is applied. One skilled inthe art can readily determine the appropriate weight ratios for aspecific application.

In the present invention, the weight ratio of component (A) to component(B) preferably ranges from about 0.01:99 to about 99:0.01, morepreferably from about 1:30 to about 30:1, and most preferably about 1:5to about 5:1.

The following approximate range of weight ratios of MTC to the followingorganic acids are also preferred according to the present invention:

    ______________________________________                                        MTC: benzoic acid     1:5    to 0.1:100                                       MTC: sodium benzoate  1:100  to 0.1:400                                       MTC: methyl paraben   1:5    to 0.01:100                                      MTC: propyl paraben   1:5    to 0.01:100                                      MTC: p-hydroxybenzoic acid                                                                          1:5    to 0.1:250                                       MTC: dehydroacetic acid                                                                             1:5    to 1:400                                         MTC: octanoic acid    1:5    to 1:400                                         MTC: nonanoic acid    1:10   to 1:400                                         MTC: formic acid      1:50   to 1:800                                         MTC: sorbic acid      1:5    to 0.1:100                                       MTC: potassium sorbate                                                                              1:5    to 1:800                                         MTC: acetic acid      1:100  to 1:200                                         MTC: oxalic acid      1:50   to 1:200                                         MTC: glycolic acid    1:100  to 1:400                                         MTC: citric acid      1:100  to 1:400                                         MTC: malic acid       1:100  to 1:400                                         MTC: propionic acid   1:10   to 1:400                                         MTC: lauric acid      1:5    to 0.1:400                                       MTC: undecylenic acid 1:5    to 0.1:500                                       ______________________________________                                    

In general, however, an effective fungicidal and bactericidal responsecan be obtained when the synergistic combination is employed inconcentrations ranging from about 0.01 to about 3000 ppm ofmethylene-bis(thiocyanate), preferably from about 0.1 to about 1000 ppm,and most preferably from about 0.1 to about 500 ppm, and from about 0.1ppm to about 1% by weight of the organic acid, preferably from about 0.1to about 5000 ppm, and most preferably from about 0.1 to about 2000 ppm.

The present invention also provides a method for controlling the growthof at least one microorganism in or on a material or medium susceptibleto attack by the microorganism which comprises the step of applying tothe material or medium a composition of the present invention, where thecomponents of the composition are present in synergistically effectiveamounts.

Furthermore, the present invention provides a method of preventingspoilage of a product, material or medium caused by bacteria and/orfungi comprising the step of applying to said product, material ormedium, a composition of the present invention where the components ofthe composition are present in synergistically effective amounts. Forexample, the composition may be used to prevent the spoilage of seeds orcrops, e.g. cotton, barley, rice, maize, tobacco, etc.

The mode and rate of application of the composition varies dependingupon the intended use of the composition. For instance, the compositionmay be applied by spraying or brushing onto a material or product. Thematerial or product could also be treated by dipping in a suitableformulation of the composition. For a liquid or liquid-like medium, thecomposition could be added into the medium by pouring, or by meteringwith a suitable device, so that a solution or a dispersion containingthe composition is produced. If used as a liquid preservative, forexample, the composition may be prepared as an aqueous emulsion. Ifnecessary, a surfactant may be added to the composition.

In accordance with the invention, additional components such asinsecticides and the like may be added to the foregoing preparationswithout affecting the synergistic effects of the composition.Insecticides that may be used include but are not limited to pyrethrins,nicotine, chlordane, parathions, and methoxychlor.

The synergistic activity of the combinations described above has beenconfirmed using standard laboratory techniques, as illustrated below.The following examples are intended to illustrate, not limit, the scopeof the present invention.

MICROBIOLOGICAL EVALUATION A. Fungal evaluation

A mineral salts-glucose medium was first prepared by adding to 1 literof deionized water: 0.7 g of KH₂ PO₄, 0.7 g of MgSO₄.7H₂ O, 1.0 g of NH₄NO₃, 0.005 g NaCL, 0.002 g FeSO₄.7H₂ O, 0.002 g ZnSO₄.7H₂ O, 0.001 gMnSO₄.7H₂ O, and 10 g of Glucose. The pH of the medium was adjusted to 6with 1N NaOH. The medium was then dispensed in 5 mL amounts into testtubes and autoclaved at 121° C. for 20 minutes.

The fungus, Trichoderma harzianum, was grown on a potato dextrose agarslant for 7 to 10 days and a spore suspension prepared by washing downthe spores from the slant into a sterile saline solution. After theaddition of biocides in the desired concentrations to the sterilemineral salts-glucose medium, the fungal spore suspension was added. Thefinal spore concentration was approximately 10⁶ cfu/mL. The inoculatedmedia was incubated at 28° C. for 14 days.

B. Bacterial evaluation

Nutrient broth (2.5 g/liter of deionized water) was prepared and the pHadjusted to 6 with 1N HCL. This was dispensed in 5 mL amounts into testtubes and autoclaved for 20 minutes at 121° C. After the addition ofbiocides in the desired concentrations to the nutrient broth, 100microliters of a suspension of Pseudomonas aeruginosa cells ofapproximately 9.3×10⁸ cfc/mL were added and incubated at 37° C. for 48hours.

In Examples 1 through 19, a synergistic effect was demonstrated bytesting the combination of methylene-bis(thiocyanate), designated ascomponent A, and the corresponding organic acid, its salt or ester,designated as component B, in a series of tests in varying ratios and arange of concentrations against the fungus Trichoderma harzianum andalso against the bacterium Pseudomonas aeruginosa, using the methodsdescribed above.

For each component A and B in a mixture containing A and B and for eachcomponent A and B acting alone, the lowest concentration whichcompletely prevented growth of the fungi for two weeks and the bacteriafor 48 hours was determined. These concentrations were used as endpoints for synergism calculations. End points for the components aloneor in mixtures described above were then compared with the end pointsfor the pure active ingredients alone in similarly prepared flasks ortest tubes.

Synergism was demonstrated by the method described by Kull, E. C.,Eisman, P. C., Sylwestrwicz, H. D., and Mayer, R. L. 1961. AppliedMicrobiology. 9:538-541 wherein:

    QA/Qa+QB/Qb is less than 1

Qa=Concentration of compound A in parts per million, acting alone, whichproduced an end point.

Qb=Concentration of compound B in parts per million, acting alone, whichproduced an end point.

QA=Concentration of compound A in parts per million, in the mixture,which produced an end point.

QB=Concentration of compound B in parts per million, in the mixture,which produced an end point.

When the sum of QA/Qa and QB/Qb is greater than one, antagonism isindicated and when the sum is equal to one, additivity is indicated.When the sum of this value is less than one, synergism exists.

This procedure for demonstrating synergism of the compositions of thisinvention is widely used and accepted. More detailed information isprovided in the article by Kull et. al. Further information concerningthis procedure is contained in U.S. Pat. No. 3,231,509, which disclosureis fully incorporated by reference.

The Examples demonstrate that in almost all of the samples, thecombination of MTC with a corresponding organic acid produced asynergistic result (indicated by a ratio value of less than one.) Therewere a few samples, such as Table 2, <1.25 or <1.5, where synergisticresults were inconclusive because endpoints for the acids used alonewere not determined.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the compositions and methodsof the present invention without departing from the spirit or scope ofthe invention. Thus, it is intended that the present invention cover themodifications and variations of this invention provided they come withinthe scope of the appended claims and their equivalents.

    ______________________________________                                        Example 1                                                                     Component A = MTC                                                             Component B = Benzoic acid                                                           Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    2.5    --    250  0.25  0.5   0.75                                      --    5.0    --    25   0.5   0.05  0.55                                      --    5.0    --    50   0.5   0.1   0.6                                       --    5.0    --    100  0.5   0.2   0.7                                       --    5.0    --    250  <0.5  <0.5  <1                                        --    --     500   --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.1    --    25   0.1   0.1   0.2                                       --    0.1    --    50   0.1   0.2   0.3                                       --    0.1    --    100  0.1   0.4   0.5                                       --    0.25   --    25   0.25  0.1   0.35                                      --    0.25   --    50   0.25  0.2   0.45                                      --    0.25   --    100  0.25  0.4   0.65                                      --    0.5    --    10   0.5   0.04  0.54                                      --    0.5    --    25   0.5   0.1   0.6                                       --    0.5    --    50   0.5   0.2   0.7                                       --    0.5    --    100  0.5   0.4   0.9                                       --    --     250   --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 2                                                                     Component A = MTC                                                             Component B = Sodium benzoate                                                        Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    5      --     500 0.5   0.25  0.75                                      --    5      --    1000 0.5   0.5   <1                                        --    5      --    2000 0.5   1     <1.5                                      --    --     >2000 --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.25   --    1000  0.25 1     <1.25                                     --    0.5    --     250 0.5   0.25  0.75                                      --    0.5    --     500 0.5   0.5   <1                                        --    0.5    --    1000 0.5   1     <1.5                                      --    --     >1000 --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 3                                                                     Component A = MTC                                                             Component B = Sorbic acid                                                            Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    0.5    --    500  0.05  0.5   0.55                                      --    1      --    500  0.1   0.5   0.6                                       --    2.5    --    250  0.25  0.25  0.5                                       --    2.5    --    500  0.25  0.5   0.75                                      --    5      --    25   0.5   0.03  0.53                                      --    5      --    50   0.5   0.05  0.55                                      --    5      --    100  0.5   0.1   0.6                                       --    5      --    250  0.5   0.25  0.75                                      --    5      --    500  0.5   0.5   1                                         --    --     1000  --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.1    --    100  0.1   0.4   0.5                                       --    0.25   --    100  0.25  0.4   0.65                                      --    0.5    --    10   0.5   0.0.4 0.54                                      --    0.5    --    25   0.5   0.1   0.6                                       --    0.5    --    50   0.5   0.2   0.7                                       --    0.5    --    100  0.5   0.4   0.9                                       --    --      250  --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 4                                                                     Component A = MTC                                                             Component B = Potassium sorbate                                                      Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    2.5    --    250  0.25  0.13  0.38                                      --    2.5    --    500  0.25  0.25  0.5                                       --    2.5    --    1000 0.25  0.5   0.75                                      --    2.5    --    2000 0.25  1     <1.25                                     --    5      --    25   0.5   0.01  0.51                                      --    5      --    50   0.5   0.03  0.53                                      --    5      --    100  0.5   0.05  0.55                                      --    5      --    250  0.5   0.13  0.68                                      --    5      --    500  0.5   0.25  0.75                                      --    5      --    1000 0.5   0.5   <1                                        --    5      --    2000 0.5   1     <1.5                                      --    --     >2000 --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.5    --    500  0.5   0.5   <1                                        --    0.5    --    1000 0.5   1     <1.5                                      --    --      1000 --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 5                                                                     Component A = MTC                                                             Component B = p-hydroxybenzoic acid                                                  Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    2.5    --    1000 0.25  0.5   0.75                                      --    2.5    --    2000 0.25  1     1.25                                      --    5      --    25   0.5   0.01  0.51                                      --    5      --    50   0.5   0.03  0.53                                      --    5      --    100  0.5   0.05  0.55                                      --    5      --    250  0.5   0.13  0.63                                      --    5      --    500  0.5   0.25  0.75                                      --    5      --    1000 0.5   0.5   1                                         --    5      --    2000 0.5   1     1.5                                       --    --     >2000 --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.1    --    100  0.1   0.2   0.3                                       --    0.1    --    250  0.1   0.5   0.6                                       --    0.25   --    100  0.25  0.2   0.45                                      --    0.25   --    250  0.25  0.5   0.75                                      --    0.5    --    5    0.5   0.01  0.51                                      --    0.5    --    10   0.5   0.02  0.52                                      --    0.5    --    25   0.5   0.05  0.55                                      --    0.5    --    50   0.5   0.1   0.6                                       --    0.5    --    100  0.5   0.2   0.7                                       --    0.5    --    250  0.5   0.5   1                                         --    --       500 --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 6                                                                     Component A = MTC                                                             Component B = Dehydroacetic acid                                                     Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    2.5    --    50   0.25  0.1   0.35                                      --    2.5    --    100  0.25  0.2   0.45                                      --    2.5    --    250  0.25  0.5   0.75                                      --    5      --    25   0.5   0.05  0.55                                      --    5      --    50   0.5   0.1   0.6                                       --    5      --    100  0.5   0.2   0.7                                       --    5      --    250  0.5   0.5   1                                         --    --     500   --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.25   --    100  0.25  0.4   0.65                                      --    0.5    --    50   0.5   0.2   0.7                                       --    0.5    --    100  0.5   0.4   0.9                                       --    --     250   --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 7                                                                     Component A = MTC                                                             Component B = Propionic acid                                                         Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    5      --    50   0.5   0.03  0.53                                      --    5      --    100  0.5   0.05  0.55                                      --    5      --    250  0.5   0.13  0.63                                      --    5      --    500  0.5   0.25  0.75                                      --    5      --    1000 0.5   0.5   <1                                        --    --     2000  --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.25   --    100  0.25  0.4   0.65                                      --    0.5    --    50   0.5   0.2   0.7                                       --    0.5    --    100  0.5   0.4   0.9                                       --    --      250  --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 8                                                                     Component A = MTC                                                             Component B = Methyl paraben                                                         Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    1      --    500  0.1   0.5   0.6                                       --    2.5    --    50   0.25  0.05  0.3                                       --    2.5    --    100  0.25  0.1   0.35                                      --    2.5    --    250  0.25  0.25  0.5                                       --    2.5    --    500  0.25  0.5   0.75                                      --    5      --    25   0.5   0.03  0.53                                      --    5      --    50   0.5   0.05  0.55                                      --    5      --    100  0.5   0.1   0.6                                       --    5      --    250  0.5   0.25  0.75                                      --    5      --    500  0.5   0.5   <1                                        --    --      1000 --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.1    --    1000 0.1   1     1.1                                       --    0.25   --    500  0.25  0.5   0.75                                      --    0.25   --    1000 0.25  1     1.25                                      --    0.5    --    50   0.5   0.05  0.55                                      --    0.5    --    100  0.5   0.1   0.6                                       --    0.5    --    250  0.5   0.25  0.75                                      --    0.5    --    500  0.5   0.5   <1                                        --    0.5    --    1000 0.5   1     1.5                                       --    --     >1000 --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 9                                                                     Component A = MTC                                                             Component B = Propyl paraben                                                         Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    1      --    250  0.1   0.5   0.6                                       --    2.5    --    50   0.25  0.1   0.35                                      --    2.5    --    100  0.25  0.2   0.45                                      --    2.5    --    250  0.25  0.5   0.75                                      --    2.5    --    25   0.5   0.05  0.55                                      --    5      --    50   0.5   0.1   0.6                                       --    5      --    100  0.5   0.2   0.7                                       --    5      --    250  0.5   0.5   1                                         --    --       500 --   --     --   --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.1    --    500  0.1   0.5   0.6                                       --    0.1    --    1000 0.1   1     <1.1                                      --    0.25   --    250  0.25  0.25  0.5                                       --    0.25   --    500  0.25  0.5   0.75                                      --    0.5    --    5    0.5   0.00  0.5                                       --    0.5    --    10   0.5   0.01  0.51                                      --    0.5    --    25   0.5   0.03  0.53                                      --    0.5    --    50   0.5   0.05  0.55                                      --    0.5    --    100  0.5   0.1   0.6                                       --    0.5    --    250  0.5   0.25  0.75                                      --    0.5    --    500  0.5   0.5   <1                                        --    --     >1000 --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 10                                                                    Component A = MTC                                                             Component B = Nonanoic acid                                                          Quantities producing end points (ppm)                                                                              Q.sub.A /Q.sub.a +                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                            Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                  ______________________________________                                        Trichoderma                                                                            10    --     --   --   --    --    --                                harzianum                                                                              --    2.5    --   250   0.25 0.5   0.75                                       --    5      --   100  0.5   0.2   0.7                                        --    5      --   250  0.5   0.5   <1                                         --    --     500  --   --    --    --                                Pseudomonas                                                                             1    --     --   --   --    --    --                                aeruginosa                                                                             --    0.25   --   100   0.25 0.4   0.65                                       --    0.5    --    5   0.5   0.02  0.52                                       --    0.5    --    10  0.5   0.04  0.54                                       --    0.5    --    25  0.5   0.1   0.6                                        --    0.5    --    50  0.5   0.2   0.7                                        --    0.5    --   100  0.5   0.25  0.75                                       --    --     250  --   --    --    --                                ______________________________________                                    

    ______________________________________                                        Example 11                                                                    Component A = MTC                                                             Component B = Octanoic acid                                                          Quantities producing end points (ppm)                                                                              Q.sub.A /Q.sub.a +                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                            Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                  ______________________________________                                        Trichoderma                                                                            10    --     --   --   --    --    --                                harzianum                                                                              --    2.5    --   50   0.25  0.1   0.35                                       --    2.5    --   100  0.25  0.2   0.45                                       --    2.5    --   250  0.25  0.5   0.75                                       --    5           25   0.5   0.05  0.55                                       --    5      --   50   0.5   0.1   0.6                                        --    5      --   100  0.5   0.2   0.7                                        --    5      --   250  0.5   0.5   <1                                         --    --     500  --   --    --    --                                Pseudomonas                                                                             1    --     --   --   --    --    --                                aeruginosa                                                                             --    0.25   --   100  0.25  0.4   0.65                                       --    0.5    --   50   0.5   0.2   0.7                                        --    0.5    --   100  0.5   0.4   0.9                                        --    --     250  --   --    --    --                                ______________________________________                                    

    ______________________________________                                        Example 12                                                                    Component A = MTC                                                             Component B = Undecylenic acid                                                       Quantities producing end points                                                                                    Q.sub.A /Q.sub.a +                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                            Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                  ______________________________________                                        Trichoderma                                                                            10    --     --   --   --    --    --                                harzianum                                                                              --    0.5    --   500  0.05  0.25  0.3                                        --    0.5    --   1000 0.05  0.5   0.55                                       --    1      --   500  0.1   0.25  0.35                                       --    1      --   1000 0.1   0.5   0.6                                        --    2.5    --   50   0.25  0.03  0.28                                       --    2.5    --   100  0.25  0.05  0.30                                       --    2.5    --   500  0.25  0.25  0.5                                        --    5      --   25   0.5   0.01  0.51                                       --    5      --   50   0.5   0.03  0.53                                       --    5      --   100  0.5   0.05  0.55                                             5      --   250  0.5   0.13  63                                         --    5      --   500  0.5   0.25  0.75                                       --    --     2000 --   --    --    --                                Pseudomonas                                                                             1    --     --   --   --    --    --                                aeruginosa                                                                             --    0.1    --   250  0.1   0.25  0.35                                       --    0.1    --   500  0.1   0.5   0.6                                        --    0.25   --   250  0.25  0.25  0.5                                        --    0.25   --   500  0.25  0.5   0.75                                       --    0.5    --   100  0.5   0.1   0.6                                        --    0.5    --   250  0.5   0.25  0.75                              ______________________________________                                    

    ______________________________________                                        Example 13                                                                    Component A = MTC                                                             Component B = Lauric acid                                                            Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    2.5    --    500  0.25  0.25  0.5                                       --    2.5    --    1000 0.25  0.5   0.75                                      --    2.5    --    2000 0.25  0.1   1.25                                      --    5      --    25   0.5   0.01  0.51                                      --    5      --    50   0.5   0.03  0.53                                      --    5      --    100  0.5   0.05  0.55                                      --    5      --    250  0.5   0.13  0.68                                      --    5      --    500  0.5   0.25  0.75                                      --    5      --    1000 0.5   0.5   1                                         --    5      --    2000 0.5   1     1.5                                       --    --     >2000 --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.25   --    500  0.25  0.5   0.75                                      --    0.25   --    1000 0.25  1     1.25                                      --    0.5    --    100  0.5   0.1   0.6                                       --    0.5    --    250  0.5   0.25  0.75                                      --    0.5    --    500  0.5   0.5   <1                                        --    0.5    --    1000 0.5   1     1.5                                       --    --     >1000 --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 14                                                                    Component A = MTC                                                             Component B = Formic acid                                                            Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    2.5    --    2000 0.25  1     <1.25                                     --    5      --    250  0.5   0.13  0.63                                      --    5      --    500  0.5   0.25  0.75                                      --    5      --    1000 0.5   0.5   <1                                        --    5      --    2000 0.5   1     <1.5                                      --    --     >2000 --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.25   --    50   0.25  0.5   0.75                                      --    0.5    --    50   0.5   0.5   <1                                        --    --       100 --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 15                                                                    Component A = MTC                                                             Component B = Acetic acid                                                            Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    1      --    2000 0.1   1     <1.1                                      --    2.5    --    2000 0.25  1     <1.25                                     --    5      --    500  0.5   0.25  0.75                                      --    5      --    1000 0.5   0.5   <1                                        --    5      --    2000 0.5   1     <1.5                                      --    --     >2000 --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.25   --    50   0.25  0.5   0.75                                      --    0.5    --    50   0.5   0.5   <1                                        --    --       100 --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 16                                                                    Component A = MTC                                                             Component B = Oxalic acid                                                            Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    5      --    1000 0.5   0.5   <1                                        --    5      --    2000 0.5   1     <1.5                                      --    --     >2000 --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.25   --    100  0.25  0.4   0.65                                      --    0.5    --    25   0.5   0.1   0.6                                       --    0.5    --    50   0.5   0.2   0.7                                       --    0.5    --    100  0.5   0.4   0.9                                       --    --       250 --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 17                                                                    Component A = MTC                                                             Component B = Citric acid                                                            Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    5      --    1000 0.5   0.5   <1                                        --    5      --    2000 0.5   1     <1.5                                      --    --     >2000 --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.25   --    100  0.25  0.4   0.65                                      --    0.5    --    25   0.5   0.1   0.6                                       --    0.5    --    50   0.5   0.2   0.7                                       --    --       250 --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 18                                                                    Component A = MTC                                                             Component B = Malic acid                                                             Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    5      --    1000 0.5   0.5   <1                                        --    5      --    2000 0.5   1     <1.5                                      --    --     >2000 --   --    --    --                                         1    --     --    --   --    --    --                               Pseudomonas                                                                            --    0.25   --    100  0.25  0.4   0.65                             aeruginosa                                                                             --    0.5    --    50   0.5   0.2   0.7                                       --    0.5    --    100  0.5   0.4   0.9                                       --    --       250 --   --    --    --                               ______________________________________                                    

    ______________________________________                                        Example 19                                                                    Component A = MTC                                                             Component B = Glycolic acid                                                          Quantities producing end points (ppm)                                                                               Q.sub.A /Q.sub.a                                                              +                                Test organism                                                                          Q.sub.a                                                                             Q.sub.A                                                                              Q.sub.b                                                                             Q.sub.B                                                                            Q.sub.A /Q.sub.a                                                                    Q.sub.B /Q.sub.b                                                                    Q.sub.B /Q.sub.b                 ______________________________________                                        Trichoderma                                                                            10    --     --    --   --    --    --                               harzianum                                                                              --    5      --    1000 0.5   0.5   <1                                        --    5      --    2000 0.5   1     <1.5                                      --    --     >2000 --   --    --    --                               Pseudomonas                                                                             1    --     --    --   --    --    --                               aeruginosa                                                                             --    0.25   --    100  0.25  0.4   0.65                                      --    0.5    --    50   0.5   0.2   0.7                                       --    0.5    --    100  0.5   0.4   0.9                                       --    --       250 --   --    --    --                               ______________________________________                                    

What is claimed is:
 1. A composition to control the growth of at leastone microorganism selected from the group consisting of bacteria, fungi,and mixtures thereof comprisingsynergistic microbicidal effectiveamounts of (A) methylene-bis(thiocyanate) and (B) at least one organicacid selected from the group consisting of propionic acid, acetic acid,formic acid, their respective salts, and mixtures thereof.
 2. Thecomposition of claim 1, wherein said bacteria or fungi is Trichodermaharzianum or Pseudomonas aeruginosa.
 3. The composition of claim 1,wherein the weight ratio of (A) to (B) is from about 0.01:99 to about99:0.01.
 4. The composition of claim 3, wherein the weight ratio of (A)to (B) is from about 1:30 to about 30:1.
 5. The composition of claim 4,wherein the weight ratio of (A) to (B) is from about 1:5 to about 5:1.6. The composition of claim 1, wherein the weight ratio ofconcentrations are from about 0.01 to about 3000 ppm ofmethylene-bis(thiocyanate), and from about 0.1 ppm to about 1% by weightof the organic acid.
 7. The composition of claim 6, wherein the weightratio of concentrations are from about 0.1 to about 1000 ppm ofmethylene-bis(thiocyanate), and from about 0.1 to about 5000 ppm of theorganic acid.
 8. The composition of claim 7, wherein the weight ratio ofconcentrations are from about 0.1 to about 500 ppm ofmethylene-bis(thiocyanate), and from about 0.1 to about 2000 ppm of theorganic acid.
 9. The composition of claim 1, wherein said organic acidis propionic acid or a salt thereof.
 10. The composition of claim 1,wherein said organic acid is acetic acid or a salt thereof.
 11. Thecomposition of claim 1, wherein said organic acid is formic acid or asalt thereof.
 12. A method of controlling the growth of at least onemicroorganism selected from the group consisting of bacteria, fungi, andmixtures thereof in or on a product, material or medium susceptible toattack by said microorganism comprising the step of applying to saidproduct, material or medium to control said growth a compositioncomprising synergistic microbicidal effective amounts of (A)methylene-bis(thiocyanate) and (B) at least one organic acid selectedfrom the group consisting of propionic acid, acetic acid, formic acid,their respective salts, and mixtures thereof.
 13. The method of claim12, wherein said bacteria or fungi is Trichoderma harzianum orPseudomonas aeruginosa.
 14. The method of claim 12, wherein saidproduct, material or medium is wood pulp, wood chips, lumber, paints,leather, adhesives coatings, animal hides, tanning liquors, paper millliquors, metalworking fluids, petrochemicals, pharmaceuticalformulations, cooling tower water, cosmetics, toiletry formulations,textiles, geological drilling lubricants or agrochemical compositionsfor crop or seed protection.
 15. The method of claim 12, wherein saidcomposition is in the form of a solid, dispersion, emulsion or solution.16. The method of claim 12, wherein said components (A) and (B) areapplied separately to the product, material or medium.
 17. The method ofclaim 12, wherein said components (A) and (B) are first combined andthen added to the product, material or medium.
 18. The method of claim12, wherein the weight ratio of concentrations are from about 0.01 toabout 3000 ppm of methylene-bis(thiocyanate), and from about 0.1 ppm toabout 1% by weight of the organic acid.
 19. The method of claim 12,wherein the weight ratio of concentrations are from about 0.1 to about1000 ppm of methylene-bis(thiocyanate), and from about 0.1 to about 5000ppm of the organic acid.
 20. The method of claim 12, wherein the weightratio of concentrations are from about 0.1 to about 500 ppm ofmethylene-bis(thiocyanate), and from about 0.1 to about 2000 ppm of theorganic acid.
 21. The method of claim 12, wherein said organic acid ispropionic acid or a salt thereof.
 22. The method of claim 12, whereinsaid organic acid is acetic acid or a salt thereof.
 23. The method ofclaim 12, wherein said organic acid is formic acid or a salt thereof.24. A method for preventing spoilage of a product, material or mediumcaused by bacteria, or fungi comprising the step of applying to saidproduct, material or medium to prevent said spoilage, a compositioncomprising synergistic microbicidal effective amounts of (A)methylene-bis(thiocyanate) and (B) at least one organic acid selectedfrom the group consisting of propionic acid, acetic acid, formic acid,their respective salts, and mixtures thereof.
 25. The method of claim24, wherein said material is seeds or crops.
 26. The method of claim 24,wherein said organic acid is propionic acid or a salt thereof.
 27. Themethod of claim 24, wherein said organic acid is acetic acid or a saltthereof.
 28. The method of claim 24, wherein said organic acid is formicacid or a salt thereof.